Days of challenging in Grand Tours may be over for Sir Bradley Wiggins

Sir Bradley Wiggins, winner of last year's Tour de France, says it was 'a great decision' not to select him for this year's race. Photograph: Pa Wire/PA

Sir Bradley Wiggins's concession that he may not race the Tour de France to win again does not mark the end of his career, but it is most likely the beginning of the final phase.

At the end of April, when he discussed the possibility of going for the double of Giro d'Italia and Tour de France, the 2012 Tour winner was in upbeat mood; too upbeat as it proved. As the build-up to the Tour got underway, cycling's Modfather was far more reflective over a coffee in a Lancashire farm-shop café.

After winning the Olympic time-trial gold medal last year, Wiggins said he did not know what could top it. When he wrote his autobiographical account of 2012, My Time, he made it clear he was unsure quite how motivated he would be for the 2013 Tour, and that he feared returning in anything other than his best form.

The rise of Chris Froome means that he is no longer Team Sky's only leader, or indeed their best option, this year. ButHowever, the decision to leave Wiggins out of Team Sky's line-up for the Tour de France did not come easily to Sir Dave Brailsford, who was well aware of the controversy that would ensue and who also feared the effect it might have on his rider. But Wiggins said finding out he would not be in the Tour had come as a relief to him. "When I knew what the problem was, and I knew it wasn't going to happen, it was a weight off my shoulders," he admitted.

"The problem" was a burst bursa at the end of the IT band, where the thigh muscle is joined into his left knee, which was "inflamed, with the liquid not going anywhere". The knee became an issue after the Giro stage finish in Pescara, a week into the race, and five days before Wiggins eventually withdrew with an additional chest infection. "I could have pushed on with the chest, but I would have been going into the unknown with the knee," he said. "It was at that stage I started thinking about the Tour de France."

For those who wonder whether he might have won the Giro without any problems, Wiggins's own view is that the foul weather and the fine form of Vincenzo Nibali would probably have meant that remaining one of his dreams. Initially, Wiggins felt that if he stopped in the Giro and took a few days off he could regain fitness in time to race the Tour of Switzerland as a build-up to the Tour. When that notion was dashed by a specialist, he had no option but to accept that wearing the No1 dossard on the roads of France this July would not happen.

"It was a great decision by the team," he said. "I wasn't put under pressure as defending champion. That would have been disastrous because of the element of the unknown – would the knee hold? Even if I'd been going to the Tour to do a job for Chris Froome, would I have been able to? Putting someone in the race because they've won the year before ... those years are gone. It's about performance – about picking the best nine riders."

As for what will happen once the race leaves Corsica, Wiggins believes Froome can win, but is intrigued by what Alberto Contador might have in the tank. "There's something about Contador," he said. "I wouldn't underestimate him. Either he's going to peak at the Tour, or he's not ready. Physically Chris is the favourite, but the Tour is the Tour – one crash and it's over. The first stages in Corsica will be a shitfight."

While the peloton fights its way through France, Wiggins will divide his time between his Lancashire home and the roads of Majorca, with his eyes on the time-trial world championship at the end of September. But the years of Bradley Wiggins targeting the Grand Tours may now be over.

Wiggins was speaking to the Guardian at a reception to launch an attempt on the Etape du Tour by a group of star rugby players including Paul Sampson, Kris Radlinski and Paul Sculthorpe in aid of the Joining Jack charity, which campaigns to raise awareness of Duchenne Muscular Dystrophy. For more information visit www.joiningjack.co.uk